1. Field of the Invention
The present invention pertains to polyisocyanates. More particularly, the present invention pertains to liquid polyisocyanates. Even more particularly, the present invention pertains to liquid polyisocyanates modified by the incorporation of haloamide moieties thereinto and cellular products prepared therefrom.
2. Prior Art
The production of isocyanates and polyisocyanates is, well-known. These compositions enjoy particular utility in the preparation of polymeric compositions, such as polyurethanes, isocyanurate products, carbodiimide products and the like. These latter compounds are documented.
The art has strived to produce new polyisocyanates to tailor the properties of the products derived therefrom. One of the more sought after properties to be achieved in polymeric compositions is flame retardancy. Thus, the art has taught the incorporation of flame retardants such as halogen, phosphorus, amide and similar elements and structures thereinto. It is to be appreciated from a review of the prior art, however, that the flame retardants are incorporated via the polyol reactant or as a separate reactant. Little consideration has been given to incorporating flame retardant properties via a polyisocyanate reactant.
For example, in U.S. Pat. No. 3,970,600, there is disclosed a stable, liquid homogeneous solution of isocyanurate and polyisocyanate which incorporates amide and/or acylurea thereinto. In U.S. Pat. No. 3,823,158, there is disclosed the products prepared from the reaction of (1) a mixture of a polyaryl polyisocyanate consisting of 2 to 10 benzene or methyl, ethyl or propyl substituted benzene rings having one isocyanate functional group per ring, and (2) a compound selected from the group consisting of phthalic anhydride, tetrachlorophthalic anhydride, tetrabromophthalic anhydride and chlorendic anhydride. The reaction proceeds at a temperature of between 150.degree. C. and 300.degree. C. The polyaryl isocyanate and anhydride are employed in a respective weight ratio of between 2:1 to 10:1. The resulting products are characterized by polyimide linkages.
In U.S. Pat. No. 3,637,543, there is disclosed thermally stable resins and foams derived from aromatic carboxylic acid derivatives which are polyfunctional. The products, more precisely, comprise the reaction product of (1) a benzene nucleus substituted with either an anhydride, carboxyl or acyl halide, (2) a polyaryl polyisocyanate and (3) a polyol containing at least three hydroxyl groups.
Again, it is to be appreciated that this prior art summarily fails to teach modification of the isocyanate reactant, per se, by the incorporation of halogen-containing moieties.
The present invention, as will subsequently be detailed, introduces haloamide moieties into the polyisocyanate reactant.